A Study Evaluating the Safety and Efficacy of JS212 Combination Therapy in Patients With Advanced Esophageal Squamous Cell Carcinoma

Inclusion criteria

• Male or female subjects aged 18 to 75 years (inclusive) at the time of signing the Informed Consent Form (ICF).
• Histologically or cytologically confirmed esophageal squamous cell carcinoma (ESCC) that is locally advanced, recurrent, or metastatic, and not amenable to radical treatment.
• No prior systemic anti-tumor therapy. For patients who received neoadjuvant/adjuvant therapy or radical concurrent chemoradiotherapy, the interval from the last dose of chemotherapy to disease recurrence or progression must be > 6 months to be eligible for screening.
• At least one measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST 1.1).
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Expected survival ≥ 12 weeks

Exclusion criteria

• Prior treatment with any of the following: anti-PD-1 or anti-PD-L1 antibody therapy; ADC therapy targeting EGFR and/or HER3, or ADC therapy with a topoisomerase I inhibitor as the toxic payload;
• Subjects at high risk of bleeding or esophageal fistula, e.g., lesions with large ulcers or direct invasion of vital adjacent organs such as the aorta or trachea;
• Subjects with a history of gastrointestinal perforation and/or fistula within 6 months prior to the first dose;
• Presence of active central nervous system (CNS) metastases;
• Active autoimmune disease requiring systemic therapy (e.g., corticosteroids or immunosuppressive agents) within 2 years prior to the first dose;
• Toxicities from prior anti-tumor therapy have not recovered to ≤ Grade 1 per CTCAE v6.0 or to the level specified in the inclusion/exclusion criteria;
• Severe cardiovascular or cerebrovascular disease;
• Known hypersensitivity or severe allergic reaction to the study treatment drugs, any of their components, or their excipients；